P1421 Diagnostic Code on 2009 Nissan Murano: Causes and Fixes
I'm experiencing a P1421 diagnostic code on my 2009 Nissan Murano. The issue appears to be related to the cold start emission reduction strategy, where the Engine Control Module (ECM) fails to properly manage ignition timing and engine idle speed during pre-warming conditions. No other fault codes are present, and the ECT (Engine Coolant Temperature) sensor is functioning correctly. Possible contributing factors include insufficient intake air volume, fuel injection system issues, or ECM control problems. Despite searching online forums, I'm finding limited information specifically about this code on Nissan Murano models. Can anyone confirm common fixes or diagnostic steps for P1421 in a 2009 VQ35DE engine?
P1421 - VQ35DE engine, no additional codes detected; ECT sensor is operational. The fault relates to the cold start emission reduction strategy monitoring. The ECM fails to control ignition timing and idle speed properly when the engine starts under pre-warming conditions. Potential root causes include inadequate intake air volume, fuel injection system malfunctions, or issues within the ECM itself.